WHO issues rapid-response plan for flu pandemic

Jan 27, 2006 (CIDRAP News) – The World Health Organization (WHO) has released a draft plan for nipping a potential influenza pandemic in the bud, saying that even if such an attempt fails, it may buy precious time to make more vaccine and improve other preparations.

The 16-page plan calls for using quarantine, social distancing, and antiviral drugs to try to stop an emerging pandemic flu virus, if it can be detected early enough. The WHO intends to refine the plan by Apr 1 and begin training rapid-response teams in May.

"Containment of a potential pandemic has never been attempted; the world has never before received an advance warning that a pandemic may be imminent," the "WHO Pandemic Influenza Draft Protocol for Rapid Response and Containment" states. "The practical and logistics challenges are formidable and success is not assured."

Indeed, many disease experts are skeptical that stopping an emerging pandemic is possible, given the weak public health and disease surveillance systems in many of the countries hardest hit by H5N1 avian flu, where a pandemic is considered most likely to start. Skeptics also cite the lack of a vaccine and scant supplies of antiviral drugs.

But the WHO document says the attempt should be made, because it could save millions of lives and prevent economic and social disruption.

"Even if containment efforts ultimately fail to stop the emergence of a fully fit pandemic virus, these efforts could slow the initial spread of the pandemic and give countries time to increase preparedness," the draft states.

"Each day gained following the emergence of a pandemic virus—if rapidly detected—allows the production of around 5 million doses of a pandemic vaccine. Each added day gives countries more time to adapt routine health services to an emergency situation."

In addition, efforts to develop a capability for rapid containment will help strengthen national, regional, and international health capacities, the plan says.

As reasons for hope that containment is possible, the WHO cites Hong Kong's experience with the H5N1 virus in 1997, when the destruction of all poultry prevented further avian outbreaks and human cases. The plan also mentions two mathematical modeling studies that suggested that containment may be possible under certain conditions.

The purpose of the plan is to facilitate rapid detection of potential signs that the H5N1 virus (or other potential pandemic flu strains) is becoming more transmissible among humans and to guide effective responses before the virus can escape an initial outbreak zone, the document says.

Under the plan, countries are responsible for surveillance—looking for signals indicating that a novel flu virus has begun to spread from person to person. One possible signal would be the discovery of a virus that has a hemagglutinin gene derived from a nonhuman flu virus and internal genes derived from a human flu virus. Another likely signal would be a finding that a novel flu virus has spread from one person to at least five others.

Countries are expected to report such signals to the WHO within 24 hours. The agency then will consider whether a containment effort is warranted and feasible. Containment will not be attempted if there is no laboratory confirmation of a novel flu virus or if the virus has already spread so far as to make quarantine impractical, the plan says.

If containment is attempted, the country involved will be expected to coordinate with the WHO in implementing quarantine measures, distributing and administering antiviral drugs, conducting surveillance, and implementing other public health measures. In the quarantine zone, antivirals will be used to treat sick people and to prevent illness in those with no symptoms, according to the plan.

"The concept of rapid containment depends upon the rapid availability of antiviral drugs and additional supplies and equipment," the plan notes. It says the WHO's stockpile of oseltamivir (Tamiflu) now amounts to 1.5 million treatment courses and will grow to 3 million courses by May, with another 2 million courses pledged by Roche, the manufacturer.

A number of countries are building their own stockpiles, and some regional stockpiles are planned as well, the WHO says. There is no coordination among the various stockpiles, but the WHO hopes to "define the operational relationships" among them so that they can be used in a coordinated way to support rapid response and containment.

The document doesn't address the question of whether existing antivirals will be effective against a pandemic strain. Experience with the use of oseltamivir in people infected with H5N1 has yielded little evidence of its effectiveness, though patients may have received the drug too late, according to a report published in The Lancet last week.

The WHO will mobilize and coordinate all international and regional support for an affected country, the plan promises.

The agency plans to assign three to five staff members to a working group, augmented by recruits from other organizations, to further develop the plan. The WHO timeline calls for drafting a more detailed plan by Mar 6 and then holding a global meeting in Geneva from Mar 6 to 10 to reach agreement on "fundamental concepts and standard operating procedures."

Next the agency will develop teaching materials and recruit faculty so that training of rapid-response teams can begin in May, the document says. Teams will include people with skills in laboratory diagnostics, epidemiology, clinical management, infection control, veterinary medicine, ethics, and other areas. They will receive about 2 weeks of training.

The rapid-response plan is one of three major strategies for addressing the pandemic threat, the WHO says. The other two consist of the efforts to contain H5N1 avian flu in poultry and the efforts to improve the world's general preparedness for a pandemic.